Why is #NaHCO_3# used to neutralize #H_2SO_4# and not #NaOH#?
I suspect that it is for safety reasons.
Both substances will neutralize sulfuric acid perfectly well.
But solid sodium hydroxide is more corrosive to human skin than sodium hydrogen carbonate is.
Also, the concentration of hydroxide ions in a solution of sodium hydrogen carbonate is much less than in a solution of sodium hydroxide with the same molarity.
So, a spilled solution of sodium hydrogen carbonate will be less caustic than a solution of sodium hydroxide.